Flat Roof: Corrugated Steel

Paroc Air is a simple and safe solution for making dry flat roofs. PAROC Air keeps the roof structure dry without any mechanical systems. The basis for this simple but effective solution is natural air pressure.

Effective roof insulation has three or four insulation layers. The lowest insulation layer forms a uniform base for the vapour barrier. The vapour barrier prevents moist air from leaking into the insulation layer. Due to the continuous stone wool base, the vapour barrier remains intact even during small structural movements.

The top of the intermediate insulation layer has a series of grooves which forms a network of ventilation channels. Porous stone wool with high vapour permeability doesn’t absorb the moisture into the insulation but allows moisture to move to the ventilation grooves where it is led out from the construction through ventilation hoods.

On the top of the grooved insulation layer there is a thin and rigid stone wool board. It covers the ventilation channels and carries the load from human traffic during installation and maintenance.

Use one-layer insulation system for structures with an insulation thickness that is less than or equal to 180 mm. Install the roofing membrane directly on the insulation. Mount the insulation slabs with glue or mechanical fasteners through the membrane. Always install a vapour barrier under the insulation layer regardless of the supporting structure.

For further information about the FM 4470 system and the components that shall be used we recommend visit www.roofnav.com where you will find a tool for calculating FM 4470 approved roof solution.

A two-layer insulation system consists of a thicker insulation layer with a thin rigid roof board on the top. The thickness of the main insulation layer varies between 50 and 200 mm and the top board from 20 to 50 mm. The top layer distributes the load. The advantage of a two-layer insulation system over a one-layer system is improved energy efficiency. The two-layer insulation system has no slab joints going through the whole insulation layer.

For further information about the FM 4470 system and the components that shall be used we recommend visit www.roofnav.com where you will find a tool for calculating FM 4470 approved roof solution.

Passive house insulation requires up to five layers of insulation. This solution is useful for Paroc ventilated roofs, where the upper intermediate layer has grooves in the surface. We recommend the ventilated solution as the number one solution, because it brings extra safety to the building.

Roofing membrane

Mechanical fasteners

PAROC ROS 80t (d1)

PAROC ROS 30g (d2)

PAROC ROS 30 (d3 + d4)

Vapour barrier

ROS 50 (d5)

Load bearing steel

Block of flats

Recommended U-value

W/m2K

0.06 - 0.09

d1

mm

20

d2

mm

110

d3 + d4

mm

180 + 180

d5

mm

50

Total insulation thickness

mm

540

Notes:
According to the definition of a passive house provided by the Passive House Institute, the annual heating, cooling and primary energy demand should not exceed certain values. Although good thermal insulation plays a major role in achieving the Passive House standard, it alone cannot ensure compliance. The requirements for other building components and devices can be determined by various calculations tools, such as the Passive House Planning Package (PHPP), available at www.passiv.de.

Grooves have been calculated as one separate construction layer: depth 20 mm, 15 % of area.

Mechanical fasteners: CROCO B-110 + KLA-screw

Fasteners/m², nf, 4

Thickness of the fastener,D, 5.00 mm

The effect of fasteners with the construction layers presented is less than 3 %, so the fasteners do not need to be taken into account.

As a pioneer in the insulation industry Paroc aims to fulfil the changing demands today’s world sets for the environments we build for ourselves. Sustainable and durable choices can ensure fire safe, energy-efficient and comfortable living and working environments in the future. Our reliable solutions and unique ability to innovate encourage others to follow us. By staying ahead of the competition and achieving growth, we can ensure the development of our solutions, operations, and employees. We are open in our operations as we think that by inspiring others we can shape the entire construction industry.